kobject_add_internal failed for hci6:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci6: failed to register connection device ================================================================== BUG: KASAN: use-after-free in l2cap_sock_new_connection_cb+0x1f5/0x2a0 net/bluetooth/l2cap_sock.c:1527 Read of size 8 at addr ffff888075f4b548 by task kworker/u5:5/4281 CPU: 0 PID: 4281 Comm: kworker/u5:5 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: hci6 hci_rx_work Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 l2cap_sock_new_connection_cb+0x1f5/0x2a0 net/bluetooth/l2cap_sock.c:1527 l2cap_connect_cfm+0x35f/0x1120 net/bluetooth/l2cap_core.c:8392 hci_connect_cfm+0x8f/0x130 include/net/bluetooth/hci_core.h:1814 le_conn_complete_evt+0x10ec/0x1670 net/bluetooth/hci_event.c:5882 hci_le_conn_complete_evt+0x183/0x440 net/bluetooth/hci_event.c:5908 hci_event_func net/bluetooth/hci_event.c:7412 [inline] hci_event_packet+0x7b6/0x1280 net/bluetooth/hci_event.c:7467 hci_rx_work+0x3eb/0xd40 net/bluetooth/hci_core.c:4083 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 4281: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc+0xb0/0x240 mm/slab_common.c:949 kmalloc include/linux/slab.h:568 [inline] sk_prot_alloc+0xe7/0x210 net/core/sock.c:2052 sk_alloc+0x36/0x340 net/core/sock.c:2108 bt_sock_alloc+0x36/0x130 net/bluetooth/af_bluetooth.c:148 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1924 [inline] l2cap_sock_new_connection_cb+0xde/0x2a0 net/bluetooth/l2cap_sock.c:1512 l2cap_connect_cfm+0x35f/0x1120 net/bluetooth/l2cap_core.c:8392 hci_connect_cfm+0x8f/0x130 include/net/bluetooth/hci_core.h:1814 le_conn_complete_evt+0x10ec/0x1670 net/bluetooth/hci_event.c:5882 hci_le_conn_complete_evt+0x183/0x440 net/bluetooth/hci_event.c:5908 hci_event_func net/bluetooth/hci_event.c:7412 [inline] hci_event_packet+0x7b6/0x1280 net/bluetooth/hci_event.c:7467 hci_rx_work+0x3eb/0xd40 net/bluetooth/hci_core.c:4083 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 18006: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700 sk_prot_free net/core/sock.c:2091 [inline] __sk_destruct+0x4ba/0x650 net/core/sock.c:2177 l2cap_sock_cleanup_listen+0xda/0x270 net/bluetooth/l2cap_sock.c:1492 l2cap_sock_release+0x66/0x1e0 net/bluetooth/l2cap_sock.c:1453 __sock_release net/socket.c:654 [inline] sock_close+0xd5/0x240 net/socket.c:1399 __fput+0x22c/0x920 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 get_signal+0x11a6/0x1350 kernel/signal.c:2648 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888075f4b000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1352 bytes inside of 2048-byte region [ffff888075f4b000, ffff888075f4b800) The buggy address belongs to the physical page: page:ffffea0001d7d200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75f48 head:ffffea0001d7d200 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888017442000 raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 16881, tgid 16881 (syz-executor), ts 1520752901354, free_ts 1520701284223 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559 prep_new_page mm/page_alloc.c:2566 [inline] get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657 alloc_slab_page+0x5d/0x160 mm/slub.c:1799 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2c0 mm/slub.c:1997 ___slab_alloc+0xbc6/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc_node_track_caller+0x9e/0x230 mm/slab_common.c:956 kmalloc_reserve net/core/skbuff.c:446 [inline] pskb_expand_head+0x1a6/0x12a0 net/core/skbuff.c:1848 netlink_trim+0x180/0x220 net/netlink/af_netlink.c:1299 netlink_broadcast+0x75/0x10d0 net/netlink/af_netlink.c:1500 nlmsg_multicast include/net/netlink.h:1071 [inline] nlmsg_notify+0xe7/0x1a0 net/netlink/af_netlink.c:2554 rtnl_notify net/core/rtnetlink.c:796 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:3990 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4005 [inline] rtnetlink_event+0x13a/0x1a0 net/core/rtnetlink.c:6201 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455 __netdev_upper_dev_link+0x41e/0x590 net/core/dev.c:7776 netdev_master_upper_dev_link+0xb9/0x100 net/core/dev.c:7846 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1486 [inline] free_pcp_prepare mm/page_alloc.c:1536 [inline] free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508 free_slab mm/slub.c:2036 [inline] discard_slab mm/slub.c:2042 [inline] __unfreeze_partials+0x1a5/0x200 mm/slub.c:2591 put_cpu_partial+0x17c/0x250 mm/slub.c:2667 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3383 prepare_creds+0x3c/0x610 kernel/cred.c:260 access_override_creds fs/open.c:376 [inline] do_faccessat+0xeb/0xa10 fs/open.c:440 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Memory state around the buggy address: ffff888075f4b400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888075f4b480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888075f4b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888075f4b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888075f4b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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